title: Proximate nutrient analyses of four species of submerged aquatic vegetation consumed by Florida manatee (Trichechus manatus latirostris) compared to romaine lettuce (Lactuca sativa var. longifolia).
abstract: Free-ranging Florida manatees (Trichechus manatus latirostris) consume a variety of sea grasses and algae. This study compared the dry matter (DM) content, proximate nutrients (crude protein [CP], ether-extracted crude fat [EE], nonfiber carbohydrate [NFC], and ash), and the calculated digestible energy (DE) of sea grasses (Thalassia testudinum, Halodule wrightii, and Syringodium filiforme) collected in spring, summer, and winter, and an alga (Chara sp.) with those of romaine lettuce (Lactuca sativa var. longifolia). Neutral-detergent fiber (NDF), acid-detergent fiber (ADF), and lignin (L) measured after ash-extraction were also compared. Results of statistical tests (C = 0.01) revealed DM content was higher in aquatic vegetation than in lettuce (P = 0.0001), but NDF and ADF were up to threefold greater, EE (P = 0.00001) and CP (P = 0.00001) were 2-9 times less, and NFC (P = 0.0001) was 2-6 times lower in sea grass than in lettuce, on a DM basis. Chara was lower in NDF, ADF, L, EE, CP, and NFC relative to lettuce on a DM basis. Ash content (DM basis) was higher (P = 0.0001), and DE was 2-6 times lower in aquatic vegetation than in lettuce. Sea grass rhizomes had lower L and higher ash contents (DM basis) than sea grass leaves. Based on the nutrient analyses, romaine lettuce and sea grasses are not equivalent forages, which suggests that the current diet of captive Florida manatees should be reassessed.
authors.affiliation: College of Veterinary Medicine, University of Florida, 2015 SW 16th Avenue, Gainesville, Florida 32610, USA. jess_sw24@hotmail.com
authors.forename: Jessica L
authors.initials: JL
authors.lastname: Siegal-Willott
authors.forename: Kendal
authors.initials: K
authors.lastname: Harr
authors.forename: Lee-Ann C
authors.initials: LA
authors.lastname: Hayek
authors.forename: Karen C
authors.initials: KC
authors.lastname: Scott
authors.forename: Trevor
authors.initials: T
authors.lastname: Gerlach
authors.forename: Paul
authors.initials: P
authors.lastname: Sirois
authors.forename: Mike
authors.initials: M
authors.lastname: Reuter
authors.forename: David W
authors.initials: DW
authors.lastname: Crewz
authors.forename: Richard C
authors.initials: RC
authors.lastname: Hill
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D000835:Animals, Wild; D005247:Feeding Behavior; D018545:Lactuca / Q000737:chemistry*; D009753:Nutritive Value; D020457:Trichechus manatus / Q000502:physiology*